A Solid State Drive (SSD) which includes a NAND type flash memory has been used in place of a Hard Disc Drive (HDD) as a memory device. As the size of the NAND type flash memory is reduced, the SSD has become larger in capacity and lower in price, so that it has been widely spread in faster speed.
On the other hand, as the capacity becomes larger and the a package becomes diverse, the types of the NAND type flash memory increase, and a distribution amount of each type of NAND type flash memory in the market decreases, so that the price of the NAND type flash memory tends to be higher.
Under such circumstances, a package called Multi Chip Package (MCP) formed by stacking NAND type flash memory chips in a thickness direction of the chips has been proposed in recent years. In the MCP, chips or a chip and a substrate on which the package is mounted are bonded by bonding wires (see, for example, JP-A-2012-104707 and JP-A-2010-251762).
In order to increase the operation speed of the entire MCP, a plurality of NAND type flash memories are divided for a plurality of channels and are operated in each channel ti increase data transfer bandwidth. Therefore, it is preferable to separate bonding wires for signal communication for each channel and bond them. In this case, since noises superimposed on the wires increase as the bonding wires become longer, it is desirable to shorten the bonding wires for signal communication as much as possible.
However, in the technical field related to the above-described conventional MCP, there has been no proposal in wires bonding which considers such a problem.